I call it cp2winswitch (remember to make it executable) and store it in my ~/bin folder. It must be run with sudo, and it essentially helps you to copy single files to either the 'switch-in' or 'switch-out' folders of one or more users. Yes, it's probably overkill, but writing it was a good exercize for me and perhaps someone else will like it.
[robg adds: I haven't tested this one...]

